Visions for the future in osteoporosis research.

An ideal therapeutic agent for osteoporosis-one that both inhibits osteoclastic bone resorption and stimulates new bone formation-is not currently available. Currently available resorption inhibitors (estrogen, bisphosphonates, and calcitonin) prevent further bone loss and stabilize bone mass. However, they have a negligible to very modest effect on bone formation over prolonged periods, and do not cause prolonged increases in bone mass. A universally acceptable bone formation stimulator is not currently available. Future research is likely to focus on the use of peptide growth factors to stimulate appositional bone growth, or on the use of low molecular weight compounds that may selectively stimulate bone cells to produce these factors in the local bone remodeling microenvironment.